Very large screen (VLS), direct-view, television receivers presently are being introduced into the home entertainment markets, both in the United States and abroad. Current domestic screen sizes include 79 cm (31V) and 89 cm (35V), 110.degree. deflection tubes, in a conventional 4.times.3 aspect ratio (width-to-height). An 86 cm (34V) 106.degree. deflection tube, in a 16.times.9 aspect ratio, is about to be introduced abroad. A common yoke has been designed which can be used on all of these tube types; however, the yoke differs from prior yokes, in that it is shorter and overlies less of the tube envelope funnel.
During the operation of a television receiver, the electron beams of the tube are accelerated by high voltages applied to elements within the tube. Portions of each of the beams, which do not strike color-emissive phosphor elements on a screen, are intercepted by a shadow mask or impinge on other internal tube components, and x-rays are emitted. The tube is fabricated of x-ray absorptive glass and other shielding is utilized, to keep the level of x-ray emission below a limit of 0.5 millirem per hour (mR/h), at an anode current of 300 .mu.A, during normal operation. However, in a failure mode, in which the anode voltage exceeds design limits, x-rays can be emitted from the rear of the tube, adjacent to the yoke. With prior yokes, which extend further along the funnel, this x-radiation is partially absorbed by the yoke materials; however, the present, shorter, yokes do not extend over that portion of the funnel from which x-rays are emitted. A need thus exists for a means for attenuating the x-radiation that otherwise would be emitted from a tube, during some types of receiver failure.